Routine maintenance of air conditioning systems often involves re-supplying an air conditioning unit with fluid which may have been lost as a result of a leak in the unit, for instance, a refrigerant, a lubricant or an additive.
One way of replenishing the supply of fluid in an air conditioning system involves injecting the fluid under pressure into the air conditioning unit by way of a charging system. Typically, an aerosol-type dispenser may be used as a charging system for injecting fluid into the air conditioning unit.
In this type of charging system, it is not uncommon to provide the dispenser with a fluid comprising a combination of refrigerant and dye. The dye is injected into the air conditioning unit along with the refrigerant, and is employed to detect leaks. A visual inspection of the air conditioning unit will reveal a leak at the location where dye is seen to be escaping the system. In some cases, a fluorescent dye, made visible by exposure to ultraviolet light, may be used to identify the leak.
Where an aerosol-type dispenser is used to inject fluid, one way of directing the contents of the dispenser into the air conditioning system is to employ a tap hose. Typically, a tap hose comprises an elongated tube having a first fitting at one end for connecting to the dispenser, and a second fitting at the opposite end for connecting to the air conditioning unit. The first fitting has female threading to connect to counterpart male threading provided on the top of the dispenser. The first fitting is also provided with a piercing device, such as a pin or a needle. The piercing device is mounted within the first fitting such that when the first fitting of the tap hose is mated with the dispenser, the piercing device breaks through the flat top of the dispenser to allow the contents thereof to escape through the tube. The flow of fluid through the tube is controlled by a control valve mounted to the tap hose.
The second fitting of the tap hose is generally compatible with the low-pressure side service port of the air conditioning unit. The service port of the air conditioning unit has a pressure-actuated valve. This type of valve is known to those skilled in the art. As the second fitting is mated with the service port of the air conditioning unit, a portion of the second fitting is urged against the valve of the service port thereby causing it to be actuated.
The typical installation of a tap hose is explained below. The control valve is closed. The first fitting is then screwed onto the top of the dispenser. The mating of the first fitting to the dispenser urges the piercing device to puncture the top of the dispenser and the contents of the dispenser are allowed to flow out from the dispenser and through the tube. The second fitting is then mated to the low-pressure side service port of the air-conditioning unit and the valve of the service port is actuated. Once both fittings have been properly mated, the control valve is opened and the fluid is allowed to flow unobstructed through the tube. The pressure in the dispenser being greater than the pressure in the air conditioning unit at the service port, the fluid is injected into the air conditioning system.
The use of a tap hose to effect the fluid refilling operation in an air conditioning unit has a number of drawbacks. The tap hose may be expensive to manufacture, particularly the tap hose component which comprises the piercing device. In some instances, the cost of manufacturing a tap hose may greatly exceed the cost of the aerosol-type dispenser and its contents. In such cases, the relative high cost of manufacturing would make disposal of the tap hose after a single use infeasible and uneconomical. Accordingly, it is more likely that a tap hose will be re-used for multiple injections of fluid. However, the components of the tap hose may not be particularly well-suited for multiple use. For instance, the pin or needle of the piercing device may be susceptible to being bent or broken and the tube may be subject to wear, resulting in leakage.
As previously discussed, typical charging systems employ aerosol-type dispensers to inject fluids into air conditioning units. Often times, these types of dispensers require the use of a propellant to effect the injection of the fluid. Other times, the fluid itself will be held under pressure within the dispenser. In some jurisdictions, the content and size of these dispensers may be subject to strict regulatory control. Accordingly, the dispensers may have to comply with minimum size requirements. The sale and use of propellants are often restricted and may even be prohibited in some jurisdictions.
Alternative apparatuses and methods for injecting fluids into air conditioning systems are desirable.